1. Field of the Invention
This invention relates generally to the field of single and multi-component spray systems, and specifically to apparatus and methods for delivering a single component or a mixed multi-component material through a disposable delivery tube and atomizing the material into a spray pattern of substantially uniform dispersion where the atomization occurs without any contact between the material and the spray apparatus thereby preventing clogging of the spray apparatus. The invention also covers a method for introducing a single component material or a multi-component material through a disposable delivery tube and applying air pressure to the material as it exits the delivery tube to atomize the material into a spray pattern of substantially uniform dispersion.
2. Description of Related Art
Multi-component materials usually consist of two or more components. These components are shipped and stored separately until the time of application. Then the components must be mixed together at their specified proportion ratio. Once properly mixed, the material can be applied using conventional methods such as air spray, airless spray, dispensing or extrusion, or metering. Typically, multi-component material consist of a base material and a catalyst, or a resin and a hardener, and once mixed, these materials usually cure rapidly. Usually, it is important that the two or more materials be well mixed together in a specific proportion which is referred as a mix ratio.
In conventional systems, because the mixed material passes through the internal passageways in the spray apparatus when the spraying stops, the mixed material quickly cures within the internal passageways causing clogging. This necessitates that the user must remove the spray tip and clean the atomizer passageways and outlets or flush it with a cleaning solvent which generates potential disposal problems. In addition, in the prior art spraying apparatus and processes for spraying a single component material, the material passes through the internal passageways of the spray apparatus before it is atomized, thereby leaving the nozzle subject to clogging when the spraying is stopped.
This invention relates to an apparatus and methods for spraying a single component material or a multi-component material in a manner such that there is no physical contact between the material and the internal passageways of the spray assembly. The apparatus of this invention includes a tubular manifold having a first longitudinal opening partially therethrough of a first diameter for receiving a portion of a disposable material delivery tube having an inlet end of a first diameter and a stepped exit end of a plurality of decreasing diameters. The manifold has a smaller second longitudinal opening therein formed coaxially with the first longitudinal opening for receiving in a close fitting relationship one of the smaller stepped ends of a delivery tube so that the distal end or tip of the delivery tube projects a predetermined distance from the end of the manifold. A plurality of atomizer holes are formed in the distal end of the tubular manifold symmetrically about the second longitudinal opening. The manifold has an air passageway therethrough for connecting to a source of pressurized air.
An adjustable air cap is mounted to the distal end of said manifold for directing air passing through the atomizer holes toward the exit end of the delivery tube at a desired spray angle to atomize the material into a substantially uniform conical pattern for spraying onto a surface. The air cap is designed so that the tip of the delivery tube is substantially flush with the end of the air cap. The manifold guides and positions the delivery tube so that the tip is concentrically mounted within the air cap allowing air to uniformly flow past the tip. When the spraying of the material is concluded, the spray apparatus does not become clogged due to the fact that the sprayed material is not in contact with any internal passageways in the spray assembly. If the sprayed material sets, the disposable delivery tube can be discarded and a new one inserted for another spraying operation. Due to the elimination of the necessity to clean the spray nozzle after each material application, the need for cleaning solvents is eliminated. This makes the subject apparatus and method environmentally friendly.
The methods of this invention include introducing a material under pressure into an inlet end of a delivery tube and out through an outlet end or tip of the delivery tube. A symmetrical pattern of air under pressure is introduced into the material as it exits from the tip of the delivery tube. The air is introduced at a predetermined distance back from the tip of the delivery tube. The spray angle of the pressurized air is adjustable to atomize the material into a conical spray pattern of substantially uniform dispersion.
The subject invention is applicable to spraying any kind of material, but particularly those that are rapid curing and/or are difficult to clean upon drying or setting. The materials that can be sprayed in accordance with the principles of this invention include, without limitation, paint, glue, stucco, mastics, adhesives, sealants, foams, undercoating and other coatings.
It is the primary object of the present invention to provide a spray apparatus wherein the cleanup of the spray assembly is eliminated by using a disposable internal delivery tube and not having any spray assembly passageways to clean.
Another object of the present invention is to provide a more precisely controlled spray pattern providing a more uniform application.
Another object of the present invention is to provide improved transfer efficiency.
Further aspects of the present invention will become apparent from the following detailed description when considered in conjunction with the accompanying drawings. It should be understood, however, that the detailed description and the specific examples while representing the preferred embodiments are given by way of illustration only.